This invention relates to building construction, and particularly to a roof system for buildings, especially metal buildings with insulated roofs.
Expanded metal, metal screen, and other types of mesh have been proposed previously for use in constructing walls and ceilings of buildings. In some cases, as in U.S. Pat. No. 4,522,004, cementitious material or plaster is applied over the mesh. Mesh has also been used to support or retain insulating material, as in U.S. Pat. No. 2,148,281 and wire mesh reinforcement has been proposed, as in U.S. Pat. No. 4,047,346.
In U.S. Pat. No. 3,506,746, a net supported by poles serves as a support for receiving plaster, which hardens to form a structure in which doors and windows are subsequently cut. U.S. Pat. No. 545,301 describes a method of constructing an arched roof by applying concrete or cement to a corrugated wire mesh supported by structural beams.
U.S. Pat. No. 4,557,092 describes an insulating blanket having a strong scrim layer attached to its fiber barrier, to resist falling objects. It has been found difficult, however, to create joints of sufficient strength in such material to prevent heavy objects from falling through.
Finally, flexible materials have been used to support ceiling insulation in a dropped ceiling construction, as shown in U.S. Pat. No. 3,791,089.
None of the above patents adequately addresses the issue of worker safety, which is a particular object of this invention.
Butler Manufacturing's U.S. Pat. Nos. 5,251,415 and 5,406,764 describe roofing methods employing mesh laid over a roof prior to completion to catch dropped objects and to support insulation which is installed subsequently.
We are especially concerned with construction worker safety. Unfortunately, serious falling injuries occur from time to time during roof construction. It is therefore standard and required practice to provide safety netting or other material below roof installers to protect them and those below, and/or to require workers to be tied or tethered to the structure.
Tethers are only temporarily effective. When one neglects to apply a required tether, or while it is being moved, the workman and those below him are at risk. It would be better to have a restraint that could not be avoided, and did not require a positive act to be effective. Additionally, it would be preferable to use safety netting that would become part of the roof, to save the labor of removing the netting.